Computer processors are well known and widely used for a variety of purposes. One application of computer processors is digital signal processing (DSP). Digital signal processing is concerned with the representation of signals by sequences of numbers or symbols and the processing of these signals. DSP has a wide variety of applications and its importance is evident in such fields as pattern recognition, radio communication, telecommunications, radar, biomedical engineering, and many others. An example for a calculation algorithm used in DSP is the Discrete Cosine Transformation (DCT). The DCT transforms, e.g., image samples in an image area to DCT-coefficients ("spatial coefficients") in a frequency area. For DSP, it is often required to perform a huge number of calculation operations in a short time. Operations (such as e.g., addition a+b, multiplication a*b, power a.sup.b, logarithm log.sub.b (a), cos (a)) require execution time and hardware. Calculations are conveniently performed by hardware specialized in certain operations (e.g., adders, log-units) or by processors performing different operations. Some operations (e.g., log) can require special memory space, such as, for example, look-up tables. Both execution time and hardware are critical for modern DSP applications. Power consumption and hardware requirements, hence costs, are often larger than desired. Hence, there is a need to provide an apparatus and a method for data processing which mitigates these and other disadvantages of the prior art.